Strain-relief device.



T. J. TOBIN. STRAIN RELIEF DEVICE. APPLIOATION mum NOV. 16, 1912.

Patented June 17,1913.

5] wve when v WM/ Wessex aging 1%; :7 F 0 W UNITED STATES PATENT OFFICE.

THOMAS J. TOBIN, 0F ALBANY, NEW YORK, ASSIGNOR TO THE ERYANT ELECTRICCOMPANY, OF BBZDG-EPQRT, CONNECTICUT, A GUBlP-QRATIGN OF CONNECTICUT.

STRAIN-RELIEF DEVICE.

LOGZSAQU,

Application filed November 18, 1912.

To all who/u,M17101! comeem lie it known that l, THOMAS J. T015124, 9.citizen of the United States of America, an l residing; at lllhany, inthe county of Albany and State of New York, have in ieinted a certainnew and loiploved Slrain Relief Device. of which the "following is a.sjgeci lirration.

My invention refers to that class of (la vices related to electricfittings commonly called st 'ain relievers, and the object of myinvention is to provide an efficient device of this character, whichisboth cheaply matle and readily adjusted in use. The present (levice insome forms may also be employed as a taho'up cleviee or adjuster for asuspension eorcl.

lo the accompanying drawings, Figure l. is an elevation partly insection of a pendant installation in which my invention is em ployedboth in the suspending and in the suspei'nleel fitting: and alsoillustrating its use in mollifietl form as cord adjuster; Fig. '2 is aplan of my strain relief device in the form used in the rosette shown inFig. l; Fig". 3 is a plan of the device in the form used in thesuspended socket; Fig. 4 is a plan of the device as n'loclifiel for useas a cord adjuster; Figs. 5, t3. 7 and 8 show by way of example variousforms which may he given the device to adapt the same for use in varioustypes of fittings.

'lhe presenl strain reliol' rleviee, in its pro l lzll'ttl loxnncomprises a plate 10 of. slightly flexible izmnlaling material such asheavy w et or lihci', of an euilahlc shape. slotted to form a pair ofoppositely t'aceil tongues l1, 12. within the ma thereof. the end; oilthe tongues coimnmiicating with apertures '13, le which facilitate theadjustment of the device upon the wires 15, 16. F r use in a rosette 1?of the type shown, thecievice is sha -ml as illustrated in Fig. 2 toconform swhslanlially to the inner outline of the cap il of the rosette.Before attaching the wires to the terminals 19, 52 0 of the rosette,they are passed up through the holes 13 and I lol? the strain reliefdevice, and pulled no erally so as displace upwardly the tongues 11 and12, as shown in Fig. 1.. Sutlieient wire is l. lowed above the plate 19not only to permit the attachment'of the Wire enZis to the terminals onthe base of the rosette but Specification of Letters I'atent.

.iatenlietl June 17, 1913.

Serial No. 731,816.

also in insure sufiieient wire play to permit the plate 1.0 to restagainst the inner face of the cap 18 WlillOUt strain on the terminals.

The tlOfi'ilWillll drag of the Wires against, the ends of the tongues lland 12- tends to force these entls downward. and thus to gri p the wiresbetween the ends of the tongues and the edges of the cuts in the body ofthe plate 10 which form the tongues. The heavierthe pull upon the Wiresthe tighter they are clanmed by the tongues. This contlition is reversedat the pendent fitting, here shown as socket 21. The wires are downwardthrough the holes in the plate-'10, here disk shaped to correspond tothe interior 0' the cap of the socket. The tongues are displaced (low'wartlly and the weight of the tilting or accidental pull thereon, as inthe case of a pendent switch, tends to clamp the wires tightly betweenthe ends of the tongues and. the edges of cuts Which form. the tonguesas above described.

While the wire apertures when used are preferal'ily formed asperforations adjacent the free ends of the tongues. they may he forniotlas slots 22. Iii-3. opening from the edges of the plate ll to free endsof the tongues, o5 shown in .l igg. In this case, the plate may he useda. coral. adjuster, the Wires l)()ll;{"l)fi55t(.ltogether into one slotand engaged by one tongue, looped at 23 and then passed to her into theother slot, as shown in Fig. l. in this oonatruotion the slots should heso formed as to detract as little as po ihle from the rigidity of thosewrtions of the plate i l Wil in are adjacent the ends 0% the damping:liflilQ IZQS, since otherwise strain upon. the ooros is apt to warn thepiece aml (leer-ease its elli-l'riehcy.

"llihe various forms shown in Figs. 5 to 8 illustrate ihe allagfrtati hioi the piece to some of its various; utili F. in Fig. 5 iS shaped to theinner certain gener all used. conduit (my. .l'in rs. Figs. o ancl 'l thepieee i 4 ml to well lmown rosettes o't other to than that shown inFig. 1. While Fig. 8 i a flush receptacle of 1 other forms willrealli'qgest lllll'llSGlYQS. In all the forms it 1 understood that thethreading aperture-s may he omitted., since the essential point is llletongue "rip. and while it n'light he rlil'licnlt it would still an type.Various "W5; its adaptation to be possible to adjust the wires withoutthe threading apertures adjacent the free ends of the tongues.

I claim as nrvinvention l. A, dcxice of the character describedcomprisinga substantially flat plate of slightly flexible in.-'ulatin;,rmaterial such as fiber, adapted to loosely lit within the cap of anelectrical fitting. said plate being cut to form independent wirepassages, the 0pposed edges of each cut so closely approaching" eachother as to ctl'ect a gripping action upoxrthc wire in adjusted positionunder strain conditions.

21A device of the character described crnnprisinp .2 plate of slightlyflexible insulatinp; material and a pair of gripping tongues formed inthe body thereof, said body having independent apertures formed. thereinadjacent the free end of each tongue the purpose described.

A device of the character described, comprising' a plate of slightlyflexible insulating .niaterial and a pair ,of oppositely faced grippingtongues formed in the body thcreofi said body having; independentapertures formed therein adjacent the free end of each tongue for thepurpose described.

t. A device of the character described,

comprising a plate of insulating material and an insulating tongueformed therein and abutting at its free end a relatively rigid portionof the body of the plate, the

latter being apertured to one side of the free 5. A device of thecharacter described,

compriaiua a plate of slightly flexible insulating material and a'tongncformed therein and abutting at its free end a relatively rigid portionof the plate, to form a clamp fa an electric conducton said tongue inthe :uljustcd position of the device, being flexed from the'plane of theplate and gripping said conductor between the free end of the tongueandthe abutt inn rigid portion of the plate, substantially-as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS J. TOBIN.

Witnesses Gnome A. CAMLION, Jonx EBEL CAMPION.

